Hammer mill



H. E. KORUM HAMMER MILL June Z, 1945.

Original Filed Sept. 27, 1937 |4` 3 INVENTOR.- 45 40 44 HENRY E. KORUM 43 F'G. 7 ATTORNEYS.

Patented June 26, 1945 Henry E. Komm, Moline, Ill., assigner to Deere &

Company, Moline, Ill., a corporation -of.l1linois Original application September 27, 1937, Serial No. 165,857. Divided and this application `September 9;' 1940, Serial No. 355,977

9 Claims.

mer mills and is more particularly concerned with new and useful improvements in the rotor of the hammer mill. This .application is a division of a cao-pending application, Serial No. 165,- 857, led September 27, 1937, on which Patent 2,291,815 was issued August 4, 1942.

The principal object of the present invention is the provision of a hammer mill in which the capacity is materially increased and the power requirements materially reduced. Heretofore,

mills of this type have been provided with rotors having atleast four banks or rows of hammers and most of them are provided with six or more banks. I have discovered, however, that by providing only three banks of hammers on a hammer mill rotor, l have `been lable to materially increase the capacity of a mill of given dimensions and the power requirements of such mill for a given output are greatly reduced. In fact, tests have indicated that a mill constructed according to the present invention, has substantially fifty per cent increased capacity with the same power input as compared with a similer type of mill but having the hammer banks dirvposed closer together.

More specifically, therefore, it is an object of this invention to provide a rotor for a hamme1 mill or the like in which only three banks or v rows of hammers are employed and in which the rotor is particularly constructed so as to have a relatively large unobstructed space between each of the three banks of hammers. Another object of the present invention in this connection is the provision of hammers formed with grinding or cutting edges that are particularly arranged to permit a dispositionof the hammers so as to deflect the material in different directions, not only as regards the hammers of'each bank, but also as regards the different banks.

A further object of the present invention is the provision of a hammer mill having hammers, each Aof which is provided with step cuts and sharp cutting edges whereby the hammers out as they grind and reduce the material faster than heretofore and without the usual tendency to sliver fibrous material.

Still another objectof the present invention is toy provide a hammer mill which can be converted from a mill adapted particularly to grind small grains kinto a mill especially arranged to handle fodder or other stalkor fibrous materials. In this connection it is an object of the invention to provide a rotor with knives so arranged as to be interchanged with certain of the ham- (Cl. The present invention relates generally to hammers, the function of the knives being to out stalk and brous materials into relatively short lengths to facilitate theirvfurther reduction vby the hammers of the rotor.

These and other objects and advantages of the present invention will be apparent to those lskilled in the art after a consideration of the following detailed description, taken in conjunctionwith the accompanying drawing illustrating the preferredform of the invention.

In the drawing: l Y Figure 1 is an end elevation of a hammer vmill rotor constructed according to the principles of the present invention and showing a part of the rst plate broken away to better illustrate the construction and method of supporting the hammers; V

Figuref 2 is a sectional. `elevati-on taken along aline 2,-,2 in Figurevl; y I Figures 3, 4 and 5 are sections taken,` respectively, along the lines '3-3, 4 4 yand 5-5 of Figure 1, and illustrate .the Varying arrangement of the hammers shown-in Figure 6 on the rotor, these figuresalso showing the employment-of knives` in place of -certain of the hammerswhen rthe .-millis used rtogrind roughage and. other fibrous materials of considerable length; Figure 6is an enlarged perspective view of one 0f the hammers with which the rotor of the mill is equipped;A l

Figure 7 is an enlarged section taken through one of the knives, as along a line I-l of Figure 3; and Y Figure -8 is a fragmentary View ofthe rotor casing of the rotor, as described in my co-pendl ing application. The rotor shaft II has a central enlarged portion I2 on which are assembled a plurality of triangularplates I3, vwhich are spaced apart by spacers I4 which are generally circular castings of a diameter such that ythe lspacers I4 are ush with the edges of the triangular plates l3 when the latter are aligned so that all corresponding edges are in the same plane and the apices of the plates are aligned in an axial direction. The plates I3 and spacers I4 are slidable on the central portion I2 of the 'rotor shaft II, and a pair of lock nuts I5, i6 are disposed on opposite ends 'of the assembly of plates and spacers and engage threaded portions or banks A, B, C, each bank of hammers being supported on a single through pin 2| which extends through aligned holes in the aligned corners or apices of the triangular` plates I3. Each hammer 20 is pivotally mounted on its through pin 2| and has an aperture 22 extending transversely through the base 23 of .the hammer. The hammers 20 are each thinner than the associated spacer casting |4 and adjacent each hammer the pin 2| carries suitable spacing `washers 24. The thickness of each washer 24 is substantially equal to the thickness of the hammer and in the preferred form of construction, each spacer casting I4 is equal in thickness to a hammer and two of the associated spacing washers 24. Any suitable means, such as cotter keys 25, may be employed for maintaining the hammer supporting pins 2| in position. Normally, the hammers are not clamped rigidly between the washers 24, but are free to swing on the pin 2 I, the amount of swinging action being determined by the amount of clearance between the bases or butts 23 of the hammers 20 and the spacer castings I4, as best illustrated in Figure l. `The slight swing of the hammers which the spacing between the latter and the spacing collars I4 provides, is sufficient to accommodate the passage 'of foreign materials such as bolts, etc., through the mill without serious damage thereto.

Figure 6 shows the details of one of the hammers 20. The outer or cutting portion of the hammer is recessed to provide three cutting edges 30, 3| and 32 in spaced apart vertical planes, and the upper portion is notched to provide three transversely disposed cutting edges 33, 34 and 35. The edge 31 of the hammer between the cutting edges 30 and 3| is beveled inwardly to give a sharper angle to the cutting 'r edge 30 thereof, thereby providing more of a cutting action for increasing the speed of reduction of the material being ground in the mill but without the usual tendency to cause fibrous material to form slivers. the opposite side of the hammer is provided with similar steps of cutting edges so that the hammer is symmetrical, the same reference numerals mentioned above being applied to the cutting edges at the opposite side. The recesses in the hammer which produce the offset cutting edges 32, divide the lateral edges of the hammer substantially in two and thus provide crushing faces 38 of substantially the same width as the beveled cutting faces 31 and which are coextensive with the series of stepped faces on the other side of the hammer. Thus, the crushing faces 38 are generally parallel to the cutting edges 30, 3|, 32 and define a narrow longitudinally extending rib which terminates at the outer or upper end of the hammer in cutting edges 39 in the plane of the outer end of the hammer and in the plane of the edges 35.

As mentioned above, the hammers 20 are ar- As indicatedv in Figure 6,

ranged in three rows or banks, and to facilitate this arrangement the plates I3 are in the form of equilateral triangles, with the hammer supporting pins 2| disposed at the apices of the triangular plates. This construction is of material importance in increasing the capacity of the mill, for as' clearly shown in Figure 1 there is a relatively large open space between each two adjacent banks of hammers to receive the grain or other material to be ground and to permit the hammers to have a full contact with the material and affording all of the cutting edges a full opportunity to act upon the material. The cylindrical spacing collars I4 are flush with the sides of the triangular plates I3 so that there are no projecting parts within the space between adjacent banks of hammers to interfere with or otherwise disturb the action of the latter in striking and reducing the material to be ground. The reduced outer ends of the hammers further add to the open space between the banks.'

The hammers may be arranged on the supporting pins 2| in any suitable or desired manner, but in the preferred arrangement shown in the drawing the hammers of each bank are arranged so that some of the hammers deflect the material in one direction while other hammers in the same bank direct the material in another direction, thereby increasing the distribution of the suspended material within the zone of action of the hammers and the hammers of each bank are arranged different from the arrangement of the hammers in the other banks. As illustrated in Figure 2, the bank or row C has the two outer hammers disposed with the stepped portions facing laterally inwardly and the two central hammers arranged with their stepped portions facing laterally outwardly. Each of the hammers in the bank C is disposed substantially midway between the adjacent triangular plates I3 with one of the washers 24 on each side of each of the hammers 20. As illustrated in Figure 2, the hammers in bank B lare disposed up against the right hand plates I3 and this is accomplished by placing both of the spacing washers 24 on the left of the hammers and thus filling up the space between the latter and the left hand plates I3. It will also be seen in Figure 2 that the hammers in bank C are arranged oppositely with respect to the hammers in bank B. Specifically, in bank B the two outer hammers at each end of the rotor are disposed with their notched portions facing laterally outwardly, while in bank C as described above, the notched portions face laterally inwardly. Also, the pair of hammers in the middle of the rotor in bank B are disposed with their notched portions facing each other, while in bank C they are facing outwardly, as described above. 'I'he third bankA, Figure 1, may have its hammers arranged in any suitable manner but preferably different from either bank C or bank B; for example, each axially outer hammer may have its notched portions facing inwardly, while the four inner hammers face axially outwardly. In this way, not only are the hammers oi' each bank faced in different directions but also the hammers of the several banks are arranged differently. Furthermore, the hammers in bank A are disposed against the left hand plates I3 with the spacing washers 24 being placed on the pins 2| between the hammers and the right hand plates in a manner opposite to that described in connection with bank B. As will be obvious from Figure`6, each hammer, especially by virtue of .its bevel cut 31, has a tendency to deyect the material laterally as well as to reduce it and project the same in a generally circumferential directionaway from the rotor. In the above arrangement, it will therefore be seen that certain of the hammers tend to deflect the material laterally in one direction and other hammers tend to deileet the same laterally in another direction so as to cause different movements of air and material within the mill.

tribution of the material within the mill and insuring a uniform andl rapid reduction thereof.

The hammer mill of the present invention is particularly constructed so as to be convertible from agrain mill, that is ay mill especially adapted to grind small grain into ne particles, to a roughage mill for reducing corn stalks and other fibrous material to a coarser type of feed. When used as a grain mill, hammers only are used on the rotor, as illustrated in Figure 2, but where the mill is to be used as a roughage mill, certain of the hammers are replaced by knives, as indicated in Figures 3, 4 and 5. Each knife is indicated by the reference numeral 40 and consists of an L-shaped steel strap member having a base portion 4| that is provided with an aperture for receiving one of the pins 2| and a cutting portion 43 that is disposed generally axially of the rotor and is provided with opposite cutting edges 44 and 45, as best shown in Figure '7. As indicated in Figure 4, each knife is so formed that the cutting portion 43 thereof is disposed radially inwardly from the tips of the hammers 20 a sufficient distance zc, see Figure 4, so that the knives more effectively cut the fibers carried by the air stream. Preferably, each bank of hammers is provided with one knife, as indi- This is an important feature of the present invention in increasing the discated in Figures 4 to. 6, the knives are usually disposed in staggered relation in order to present a cutting edge over the entire width of the mill.

As best indicated in Figure 8, the knives are so formed that their cutting portions extend backward slightly with respect to the direction of rotation of the rotor, so that there is no appreciable tendency for material to cling to the edge of the knife. It is to be noted, further, that the thickness of the base portion 4l of each knife is substantially the same as the thickness of one of the hammers so that the hammers and knives are generally interchangeable with one another in any position in any of the banks of hammers.

The operation of a mill embodying the principles of the present invention is set out in detail in the above identified co-pending application, to which reference may be had if desired.

What I claim and desire to secure by Letters Patent is:

l. A hammer mill rotor comprising a rotor shaft, a series of axially aligned generally triangular plates apertured to receive said shaft, generally cylindrical collars, each having a smooth exterior surface, disposed between and spacing said triangular plates axially, three banks oi hammers pivotally connected to the apices of said aligned triangular plates, the diameter of said cylindrical collars being such that the smooth exterior surfaces of the latter lie substantially flush with the sides of said triangular plates, and the inner ends of said hammers terminating adjacent said ,collars so that the latter "serve as stops to limit the swinging movement yof the hammers about .their pivot connections. Y

2. A hammer mill' rotor having a'plur'ality of axially aligned banks of hammers with'a vplurality of hammers in each bank, each of said hammers being formed with a beveled Working edge that is adapted to deilect material laterally a certain amount, the hammers of each bankbeing arranged so that some of the hammers deect the material 'in one direction while other hammers in the same bank direct the material in another direction, thereby increasing the distribution of the suspended material within the zone of action of the hammers, and the hammers of each bank being `arranged different-from the arrangement of the hammers in the other banks with vrespect to the relative directions of deec'- tion of the various hammers to prevent the ham'- mers from establishing regular currents of material flow during operation.

3. For a hammer mill, a hammer comprising a bar having oppositely disposed beveled cutting faces formed at one side of the bar and a narrow longitudinally extending rib at the other side of the bar having parallel edge Walls affording cutting edges parallel but spaced laterally from said beveled cuttingfaces.

4. For a hammer mill, a hammer comprising a bar having a stepped outer end, opposite beveled cutting edges at one `side of the bar inwardly of the stepped portions of the latter, said edges being angled so that when the bar is applied to a hammer mill rotor the material is deflected in one direction, and when the bar is reversed on the rotor the material is deflected in another direction, and a narrow rib of uniform thickness at the outer side of the bar and extending longitudinally thereof outwardly of the beveled cutting edges to the outer portion of the stepped end of the bar.

5. In a hammer mill rotor, a plurality of sets of axially spaced hammers having flat planar edges facing generally in the direction of rotation of the rotor, and a plurality of knives carried by the rotor directly axially of the hammers and having cutting edges extending generally axially a distance greater than the axial spacing between said hammers and radially inwardly of the outer ends of said hammers for reducing corn stalks and other brous material.

6. A hammer mill rotor including a plurality of axially aligned spaced apart plates, axially directed pins carried by said plates, a plurality of hammers connected with each of said pins, spacing washers mounted on said pins and cooperating with said hammers to dispose the latter in staggered relation with respect to the hammers carried yon an adjacent axially extending pin, and a plurality of knives having axially directed cutting edges and radially disposed attaching sections mounted between certain of said plates and on said pins, said knives being substantially of the same thickness as said hammers, and

spacing washers mounted on said pins ,and associated with said knives, said last named washers being of substantially the same thickness as said rst mentioned washers, whereby a knife may be disposedin any position on the rotor in lieu of a hammer.

7. A hammer mill rotor including a plurality of plates carried by the rotor in spacedapart'relation, hammers disposed between certain of said plates, and a plurality of L-shaped cutting members disposed between certain 0f said plates and having cutting edges extending generally axially a distance greater than the axial spacing between said plates and radially inwardly of the outer ends of said hammers at a slightly inclined relation with respect to the axis of said rotor so that the rotation of the latter tends to clear the cutting edges of material that tends to cling thereto.

8. For a hammer mill, a hammer comprising a bar having at least one of its longitudinal edges formed with a series of radially spaced stepped cutting faces, at least one of which is disposed at an acute angle to the plane of rotation providing a series of longitudinally extending cutting edges, and a crushing face coextensive with said series of faces and disposed in a plane generally parallel to said cutting edges.

9. In a hammer mill for grinding feed and the like, a rotor comprising a shaft, a series of axially aligned generally triangular plates disposed on said shaft in axially spaced relation to each other and having all corresponding edges in the same plane whereby the corresponding corners of all of said plates are axially aligned in only three rows' spaced substantially 120 degrees apart, generally cylindrical collars disposed between said axially spaced plates, and three banks of hammers pivotally connected adjacent the apices of said plates, thereby providing three open unobstructed spaces between'said banks of hammers to receive the material to be ground, each of said hammers being formed with a beveled working edge that is adapted to deflect material laterally, the hammers of each bank being l arranged so that some of the hammers deect the material in one direction while other hammers in the same bank direct the material in another direction, thereby increasing the distribution of the suspended material within the zone of action of the hammers, and the hammers of each bank being arranged diierent from the arrangement of the hammers in the other banks.

' HENRY E. KORUM.

CERTIFICATE OF CORRECTION.

Patent No. 2,579,560. June 26, 19h5.

HENRY E. Komm.

It is hereby certified that error appears in the printed specification of the above numb ered patent requiring correction as follows: Page 5, second column, line 58, for the word "outer" read other-; and that the said Letters Patent should be read with this c orrection therein that the same may conform to the record of the oase in the Patent Office.

signed and Sealed this and day of october, A. D. 19LL5o Leslie Frazer (Seal) First Assistant Commissioner of Patents. 

